Japanese swimmers have been alarmed by the LZR Racer since its debut in February, with the suit accounting for 18 of the 19 new world records since then. Yamamoto said its Biorubber fabric has already been used, primarily for triathlon events. In October, swimwear by New Zealand brand Blue Seventy which used the fabric was approved by the international swimming federation FINA for its official meets, he said. Other suit makers, including Xterra of the United States, Australia's 2XU, Aquaman of France and New Zealand's Orca have also adopted the material, Yamamoto said. Five collegiate swimmers at Japan's Kansai University shaved their times by 1.0-2.0 seconds in 50 metres after switching to the Biorubber Swim fabric.

When Japanese Olympic swimmers tested the LRZ Racer last month, one of them improved his time for the first 15 metres by 0.7 seconds, said swimming federation official Norimasa Hirai. "I can imagine that in general the (Speedo) product means a difference of 0.5 seconds over 100 metres and one second over 200 metres," Hirai said.